JP4329931B2 - Tire vulcanization mold and manufacturing method thereof - Google Patents

Description

The present invention relates to a tire vulcanization mold and a manufacturing method thereof to form a pattern of a tread portion of the tire.

When forming the tread pattern on the tire, various ridge patterns corresponding to the surface of the tire tread are formed on the inner circumferential surface of the tire vulcanization mold, and the unvulcanized surface is formed on the inner circumferential surface. By pressing the green tire, a groove pattern of the tire tread portion is formed.
As for the tire vulcanization mold, a structure in which the tire is molded into a plurality of pieces in the circumferential direction has been already proposed (for example, Patent Document 1) so as to be convenient for separating the press-molded tire. In this prior art, first, after forming a substantially cylindrical member (ring-shaped workpiece) having an inner peripheral surface shape corresponding to the surface of the tread portion of the tire, a plurality of circumferential positions of the substantially cylindrical member are wired. It cut | disconnects by the electrical discharge machining (or mechanical cutting process by a wire cutting tool) from an electrode, and divides | segments into a some division | segmentation piece.
Japanese Examined Patent Publication No. 1-26866 (FIGS. 1 to 3)

However, the following problems exist in the above-described conventional technology.
That is, in a structure in which a member formed in a substantially cylindrical shape is cut and divided into a plurality of divided pieces as in the prior art, the cut surface of the cut portion is very rough as it is. When these divided pieces are assembled into a single mold for forming a raw tire, it is necessary to accurately position each divided piece. Therefore, a combined surface between the divided pieces (abutting surface, hereinafter appropriately, "Divided surface") must be finished with high dimensional accuracy (hereinafter referred to as "divided accuracy" where appropriate). For this reason, in actuality, after the above cutting, a great number of man-hours are required for precise finishing of the divided surface, resulting in an increase in manufacturing cost.
In addition, since the size of each divided piece is slightly smaller than the size at the time of cutting due to the cutting allowance at the time of cutting and the finishing allowance at the time of the finishing process, one piece may be combined in order to combine the pieces as much as possible. The same two cylindrical members are required for the manufacture of the mold, which also increases the manufacturing cost.
Furthermore, in the structure in which the divided surfaces of each divided piece having almost no gap as described above are combined, even if high-precision finishing is performed as described above, there may be a slight difference in the combined shape. It was difficult to control the dimensions.
The present invention has been made in view of the above, and an object of the present invention is to provide a tire vulcanization mold that can secure high division accuracy at a low manufacturing cost and that can easily control the gap size between divided pieces, and the mold thereof. It is to provide a manufacturing method.

In order to achieve the above object, a first aspect of the present invention is a tire add-on having a shape of an inner peripheral surface corresponding to a surface of a tread portion of a tire and configured by combining a plurality of divided pieces divided in the tire circumferential direction. In the mold for sulfur molding, at least one divided piece of the plurality of divided pieces includes a substantially round bar-shaped pin protector provided so as to protrude from a combination surface with the adjacent divided piece, and the adjacent divided pieces are provided. piece, the combination surfaces of the split pieces to be combined target, a plurality of only the grooves of the first mold in the radial direction of the cross section substantially arc shape to be fitted to the pin protector in the axial direction, at least One divided piece is provided with a plurality of radial grooves only in the radial direction of the second mold having a substantially arc-shaped cross section for fixing the pin protector.
In the present invention, a substantially round bar-shaped pin protector is provided so as to protrude from the combination surface on one side of the divided pieces to be combined, and a first concave groove corresponding to this is provided on the other side, and these are fitted. By adopting a structure in which the concave groove is fitted to the outer peripheral side of such a round bar, if only the pin protector and the first concave groove are precisely processed, the divided pieces to be assembled can be radially arranged in the circumferential direction. In addition, positioning can be performed with high accuracy, and other divided surfaces do not require high-precision processing, and for example, a cut state is sufficient.
As a result, compared with the conventional structure that required high-precision finishing for the entire divided surface, the area requiring high-precision machining can be extremely reduced, and the manufacturing cost can be reduced. In addition, such a small high-precision finishing region is fitted and combined and positioned so that the cut surfaces of the two split pieces face each other with a gap therebetween during assembly. no problem. As a result, it is not necessary to prepare the same two cylindrical members (before division) for one mold, and this can also reduce the manufacturing cost.
Furthermore, only the fitting state of the relatively small pin protector, which has been precision-finished, and the first concave groove, with the majority of the dividing surface facing the gap as described above (specifically, the diameter of the pin protector and The size of the gap between the split pieces can be determined by the size relationship of the diameter of the groove 1). Unlike the conventional structure that combines the split faces of the split pieces with almost no gap, the gap size can be controlled easily. It becomes possible to do.
According to a second aspect, in the first aspect, the second concave groove provided in the at least one divided piece and the first concave groove provided in the adjacent divided piece are substantially the same. It is characterized by having the same diameter.
A third invention is characterized in that, in the first or second invention, the at least one divided piece has the pin protector detachably attached to the combination surface.
In order to achieve the above object, a fourth aspect of the present invention is to form a substantially cylindrical member having an inner peripheral surface corresponding to the surface of a tread portion of a tire, and to divide the substantially cylindrical member at a plurality of locations in the circumferential direction. A substantially circular hole penetrating in a radial direction is drilled so as to straddle at least one scheduled split surface of the surfaces, and the substantially cylindrical member is divided into the plurality of positions including a drilling position of the substantially circular hole. One of the concave grooves each having a substantially circular cross section formed by dividing the substantially circular hole into the corresponding two divided pieces by cutting at a predetermined plane and dividing into a plurality of divided pieces. A substantially round bar-shaped pin protector is fitted and fixed in the groove of the split piece, and the pin protector is fixed to the other split piece of the substantially arc-shaped cross grooves formed in the two split pieces, respectively. To fit into the groove of Characterized by combining the two split pieces.
According to a fifth aspect of the present invention, in the fourth aspect of the invention, the combination surface in the combination of the two divided pieces is adjusted by adjusting the size relationship of the diameter of the pin protector with respect to the diameter of the concave groove of the one divided piece. It is characterized by adjusting the gap size.

  According to the present invention, a high division accuracy can be ensured at a low manufacturing cost, and the gap size between the divided pieces can be easily controlled.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing the overall structure of a tire vulcanization mold according to the present embodiment, and FIG. 2 is a top view thereof (however, a shoulder portion 3 described later is omitted for clarity). Is).
1 and 2, the tire vulcanization mold 1 is divided into a plurality (9 in this example) of division (so-called curve division) divided by division surfaces (curved surfaces) D at a plurality of locations in the tire circumferential direction. A piece (sector mold) 1A is combined in a substantially annular shape.

  3 is a cross-sectional view taken along the line III-III in FIG. 2, and FIG. 4 is an enlarged view of the main part thereof. 3 and 4, the mold 1 (in other words, each divided piece 1A) includes a tread portion 2 having a tread surface 2A having an inner peripheral surface corresponding to the surface of the tread portion of the tire, and the tread portion. 2 and a shoulder portion 3 that is abutted against the abutting surface 2B. More specifically, the tread surface 2A includes a contour surface 2Aa corresponding to the ground contact surface of the tire and a plurality of protrusions 2Ab corresponding to the grooves of the tire.

In the above basic configuration, the greatest feature of the present embodiment is the combination structure of each divided piece 1A with the adjacent divided piece 1A.
FIG. 5 is an exploded side view showing the portion A in FIG. 1 in an enlarged manner.
5 and FIG. 1, each divided piece 1A is divided into a divided surface (in other words, a combined surface) D on one side (clockwise side in FIGS. 1 and 2) of the divided surfaces D and D on both sides in the circumferential direction. A concave groove 101 (second concave groove) having a substantially arc-shaped cross section is provided. The concave groove 101 is provided with a plurality of locations (two locations in this example), for example, in the axial direction (perpendicular to the paper surface in FIG. 2) in each divided surface D. In each concave groove 101, a substantially round bar-shaped pin protector 100 is detachably fixed by a mounting bolt 103 penetrating in the circumferential direction so as to protrude from the dividing surface D (see FIG. 5).

  Correspondingly, each of the divided pieces 1A has the concave portion formed on the divided surface (combination surface) D on the other side (counterclockwise side in FIGS. 1 and 2) of the divided surfaces D and D on both sides in the circumferential direction. The pin provided in the split piece 1A to be combined, which is provided with a groove 102 (first groove) having a substantially arc-shaped cross section having substantially the same diameter as the groove 101 and facing (adjacent) in the circumferential direction. The protector 100 is fitted.

Next, the procedure of the manufacturing method of the tire vulcanization mold 1 of the present embodiment will be described step by step.
6A to 6D are diagrams showing this manufacturing procedure (process).
First, as shown in FIG. 6A, a substantially cylindrical member 1M having an inner peripheral surface shape corresponding to the surface of the tread portion of the tire is formed by a known method (turning or the like).

  Thereafter, as shown in FIG. 6 (b), a plurality of portions in the circumferential direction of the substantially cylindrical member 1M (9 places in this example) span the planned division surfaces (planned lines) Do corresponding to the aforementioned division surfaces D. A substantially circular hole T penetrating in the radial direction is drilled. The holes T are drilled with relatively high accuracy so as to satisfy a predetermined dimensional accuracy as will be described later.

  Then, as shown in FIG. 6 (c), the substantially cylindrical member 1M is cut (divided) by the nine divided surfaces including the drilling positions of the substantially circular holes T, and nine divided pieces are obtained. Divide into 1A. The cutting at this time does not require a particularly high accuracy as will be described later, and therefore, normal cutting or wire cutting, fine drilling, fine sawing, or the like is sufficient. In addition, the substantially circular hole T is divided by this cutting, and the concave grooves 101 and 102 having a substantially circular arc cross section are formed in the corresponding two divided pieces 1A and 1A, respectively.

Thereafter, as shown in FIG. 6 (d), after fitting the above-described substantially round rod-shaped pin protector 100 into the concave groove 101 of the split piece 1A on one side of the concave grooves 101, 102, the above attachment Secured with bolts 103.
When assembling all the divided pieces 1A during the molding of the tire, the pin protector 100 attached to the recessed groove 101 side of each divided piece 1A is fitted into the recessed groove 102 of the adjacent divided piece 1A to be assembled. Then, the two divided pieces 1A and 1A are combined, and this is performed for all the joining portions, and all the pieces 1A are connected to complete the tire vulcanization molding die 1.
In the above connection, by adjusting the size relationship between the diameter of the concave groove 102 of the split piece 1A and the diameter of the pin protector 100 of the split piece 1A that is the combination of the split pieces 1A, the two split pieces 1A, The gap size on the combination surface (divided surface) D in the combination of 1A is adjusted.

As described above, in the tire vulcanization molding die 1 of the present embodiment, the substantially round bar-shaped pin protector 100 is provided so as to protrude from the split surface D of the split piece 1A on one side to be combined, and the other side is provided. Corresponding grooves 102 are provided in the divided piece 1A, and these are fitted.
By adopting a structure in which the groove is fitted to the outer peripheral side of such a round bar, if the pin protector 100 (including the groove 101 to which the pin protector is attached) and the groove 102 are precisely machined, FIG. As shown, the divided pieces 1A to be assembled can be positioned with high precision both in the circumferential direction and in the radial direction, and the positional deviation between the divided pieces such as a so-called flat plate protector currently proposed and the above-described causes. The protrusion (pattern) 2Ab can be prevented from shifting or colliding. And about the divided surfaces other than the pin protector 100 (including the concave groove 101 to which the pin protector 100 is attached) and the concave groove 102, high-precision processing is not required, and for example, a cut state is sufficient.
In addition, the positioning effect also has an effect of preventing a relatively low durability portion (for example, a portion formed of aluminum, etc.) of the split piece 1A from being damaged during combination.

  As a result, compared to the conventional structure that requires high-precision finishing for the entire divided surface D, the area requiring high-precision machining can be extremely reduced, and the manufacturing cost can be reduced. In addition, such a small high-precision finished region is fitted and combined and positioned so that the cut surfaces of both divided pieces 1A and 1A face each other with a gap therebetween during assembly. There is no problem. As a result, it is not necessary to prepare the same two cylindrical members 1M in order to manufacture one mold 1, and this can also reduce the manufacturing cost.

  Further, as described above, most of the dividing surface D faces the gap, and only the fitting state of the relatively small pin protector 100 and the concave groove 102 that have been precision finished (only the pin protector as described above in detail). The size of the gap between the split pieces 1A and 1A can be determined by the relationship between the diameter of 100 and the diameter of the groove 102). For example, if the diameter of the pin protector 100 is made larger than the diameter of the concave groove 101 or the concave groove 102 (the protector 100 may be replaced or the concave groove 102 may be modified), the direction of widening the gap is increased. If it is reversed, the control is to reduce the gap. Therefore, unlike the conventional structure in which the divided surfaces of the divided pieces having almost no gap are combined, it is possible to easily control the gap size between the divided pieces 1A and 1A. In particular, since the pin protector 100 can be attached and detached with the bolt 103, various pin protectors 100 having slightly different diameters can be prepared and exchanged, and the clearance dimension can be easily adjusted. Maintenance such as replacement at 100 wear is also easy.

  In addition, in the said embodiment, in each of the division | segmentation surface D between division | segmentation piece 1A, 1A, although the coupling | bonding by the concave groove 101,102 and the pin protector 100 was performed to two axial direction places, it is not restricted to this but an axial direction Only one location is acceptable. Moreover, about all the divided pieces 1A, the adjacent divided pieces 1A have a coupling (and gap management) structure via the pin protector 100. However, the present invention is not limited to this, and such a coupling structure is formed. There may be a conventional structure that is not. In other words, it is sufficient that the pin protector 100 has a coupling structure for at least one of a large number of coupling parts of the divided pieces 1A, and as long as at least all of them are a conventional structure, The effects of reducing the original manufacturing cost and facilitating the adjustment of the gap can be obtained.

In addition, although the above demonstrated the case where this invention was applied to the metal mold | die for tire vulcanization molding as an example, it is not restricted to this, This invention is the whole divided mold which requires the function as a protector or a knock pin It is applicable to.

1 is a perspective view illustrating an overall structure of a tire vulcanization mold according to an embodiment of the present invention. It is a top view showing the whole structure of the tire vulcanization mold shown in FIG. It is a cross-sectional view by the III-III cross section in FIG. It is a principal part enlarged view of FIG. It is a disassembled side view which expands and shows the A section in FIG. It is a figure showing the manufacture procedure (process) of the tire vulcanization mold shown in FIG. It is a figure showing the behavior in positioning.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Tire vulcanization molding die, 1A ... Divided piece, 1M ... Substantially cylindrical member, 2A ... Tread surface, 100 ... Pin protector, 101 ... Concave groove (No. 2), 102... Groove (first groove), 103... Mounting bolt, D... Split surface (combination surface), Do. A substantially circular hole.

Claims (5)

In a tire vulcanization mold having a shape of an inner peripheral surface corresponding to the surface of the tread portion of the tire and configured by combining a plurality of divided pieces divided in the tire circumferential direction,
Among the plurality of divided pieces, at least one divided piece includes a substantially round bar-shaped pin protector provided so as to protrude from a combination surface with an adjacent divided piece, and the adjacent divided pieces are to be combined. The combination surface with the split piece is provided with a plurality of radial grooves only in the radial direction of the first mold having a substantially arc-shaped cross section fitted to the pin protector, and the at least one split piece is tire vulcanization mold, characterized in that it comprises a plurality only in the axial direction groove of the second mold in the radial direction of the cross section substantially arc shape for fixing the pin protector. In the tire vulcanization mold according to claim 1,
The tire vulcanization molding, wherein the second concave groove provided in the at least one divided piece and the first concave groove provided in the adjacent divided piece have substantially the same diameter. Mold. In the tire vulcanization mold according to claim 1 or 2,
The at least one divided piece has the pin protector detachably attached to the combination surface, and a tire vulcanization mold. Forming a substantially cylindrical member having an inner peripheral surface shape corresponding to the surface of the tread portion of the tire, and straddling at least one scheduled split surface among a plurality of planned split surfaces in the circumferential direction of the substantially cylindrical member; Drilling a substantially circular hole that penetrates in the radial direction,
The substantially cylindrical member is cut at the plurality of division scheduled surfaces including the drilling positions of the substantially circular holes, and divided into a plurality of divided pieces,
The substantially circular rod-shaped pin protector is fitted into the concave groove of one divided piece of the concave grooves formed in the substantially circular cross section formed in the corresponding two divided pieces by dividing the substantially circular hole by the cutting. Fixed together,
This pin protector is combined with the two divided pieces while being fitted into the groove of the other divided piece among the grooves having a substantially circular cross section formed in each of the two divided pieces. To manufacture a mold for tire vulcanization molding. In the manufacturing method of the tire vulcanization mold according to claim 4,
By adjusting the size relationship of the diameter of the pin protector with respect to the diameter of the concave groove of the split piece on one side, the clearance dimension of the combination surface in the combination of the two split pieces is adjusted. A method for producing a mold for sulfur molding.

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